1. Field of the Invention
The present disclosure features methods and compositions related to prolonging analgesic effect of local anesthetics and/or providing analgesic effect. More particularly, the disclosure invention relates to the use of cinnamaldehyde as an adjuvant to prolong analgesic effect of a local anesthetic and as an analgesic drug.
2. Description of Related Art
A local anesthetic may reversibly prevent the generation and/or the conduction of the nerve impulse in the region to which it is applied, without affecting consciousness of the subject. The prevention of the generation and/or conduction of the nerve impulse may result in the regional loss of bodily sensations, including pain, temperature, touch, and proprioception. The degree of anesthesia (including analgesia) depends on the choice and concentration of the local anesthetics and integrity of the application site. Therefore, it has long been desired to provide a more effective local anesthetic composition in terms of the duration and/or the extent of analgesia.
Transient receptor potential vanilloid (TRPV) is a family of TRP ion channels. The first member of this family being identified is TRPV1, which may be activated by a wide variety of stimuli, such as heat, acidic conditions, and endocannabinoid anandamide. Capsaicin is a TRPV1 agonist and previous studies have demonstrated a nociceptive-selective, long-lasting nerve blockade by first injecting the nearly membrane-impermeable local anesthetic QX-314, then followed by capsaicin. However, one concern is that capsaicin causes burning sensation upon injection, thereby limiting its use in clinical medicine.
In view of the foregoing, there exists in the art a need for a novel method and composition that prolongs the analgesic effect of local anesthetics.